COMMITMENTS AND CONTINGENCIES COMMITMENTS AND CONTINGENCIES (Details) $ in Millions	12 Months Ended
Dec. 31, 2023 USD ($) aircraft
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Commited to purchase (in aircraft) \| aircraft	204
Finance leased asset, Number of units \| aircraft	1
Firm aircraft commitment [Member]
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Commited to purchase (in aircraft) \| aircraft	89
Aircraft option and other rights [Member]
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Commited to purchase (in aircraft) \| aircraft	115
Minimum [Member]
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Loss Contingency, Range of Possible Loss, Portion Not Accrued	$ 10
Loss Contingency, Range of Possible Loss, Portion Not Accrued	10
Maximum [Member]
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Loss Contingency, Range of Possible Loss, Portion Not Accrued	160
Loss Contingency, Range of Possible Loss, Portion Not Accrued	160
Virgin Group trademark license agreement
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Loss Contingency, Damages Sought, Value	8
Loss Contingency, Damages Sought, Value	8
Aircraft Commitments [Member]
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
2024	1,252
2025	1,366
2026	1,097
2027	600
2028	151
Thereafter	716
Total	5,182
Capacity Purchase Agreements[Member]
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
2024	235
2025	230
2026	224
2027	220
2028	223
Thereafter	515
Total	$ 1,647
B737 MAX [Member]
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Commited to purchase (in aircraft) \| aircraft	185
B737 MAX [Member] \| Firm aircraft commitment [Member]
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Commited to purchase (in aircraft) \| aircraft	80
B737 MAX [Member] \| Aircraft option and other rights [Member]
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Commited to purchase (in aircraft) \| aircraft	105
A321neo [Member]
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Number of Aircraft Operated \| aircraft	10
E175 [Member]
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Commited to purchase (in aircraft) \| aircraft	19
E175 [Member] \| Firm aircraft commitment [Member]
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Commited to purchase (in aircraft) \| aircraft	9
E175 [Member] \| Aircraft option and other rights [Member]
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Commited to purchase (in aircraft) \| aircraft	10
Property Subject to Operating Lease [Member] \| B737-800
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Operating leases, number of leased assets (in aircraft) \| aircraft	10
Property Subject to Operating Lease [Member] \| B737 MAX [Member]
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Operating leases, number of leased assets (in aircraft) \| aircraft	14
Property Subject to Operating Lease [Member] \| E175 [Member]
Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract]
Operating leases, number of leased assets (in aircraft) \| aircraft	42

Finance leased asset, Number of units

No definition available.

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- Definition

The value (monetary amount) of the award the plaintiff seeks in the legal matter.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483076/450-20-50-1

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483076/450-20-50-4

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483076/450-20-50-9

+ Details

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- Definition

The difference between the maximum amount of estimated loss and the amount recorded as of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483076/450-20-50-4

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 450
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 9
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483076/450-20-50-9

+ Details

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- Definition

Number of aircraft operated by the carrier.

+ References

No definition available.

+ Details

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- Definition

The number of units (items of property) under operating lease arrangements.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 842
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479773/842-30-50-13

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 360
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482099/360-10-50-1

+ Details

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- References

No definition available.

+ Details

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- Definition

Amount of fixed and determinable portion of unrecorded unconditional purchase obligation to be paid in fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 440
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482648/440-10-50-4

+ Details

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- Definition

Amount of fixed and determinable portion of unrecorded unconditional purchase obligation to be paid in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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- Definition

Amount of fixed and determinable portion of unrecorded unconditional purchase obligation to be paid in fourth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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- Definition

Amount of fixed and determinable portion of unrecorded unconditional purchase obligation to be paid in second fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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- Definition

Amount of fixed and determinable portion of unrecorded unconditional purchase obligation to be paid in third fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

+ Details

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- Definition

Amount of the unrecorded obligation to transfer funds in the future for fixed or minimum amounts or quantities of goods or services at fixed or minimum prices (for example, as in take-or-pay contracts or throughput contracts).

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
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- Definition

Amount of fixed and determinable portion of unrecorded unconditional purchase obligation to be paid after fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 440
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482648/440-10-50-4

+ Details

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Balance Type:	credit
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- Definition

The minimum number of units that must be purchased, in connection with an unconditional purchase obligation that has not been recognized for financial reporting purposes.

+ References

No definition available.

+ Details

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- Details

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- Details

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- Details

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- Details

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- Details

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